On most fish, their hard, overlapping scales provide considerable protection against pokes and cuts. Because those independently-moving scales are each attached to a flexible underlying skin, however, the fish are still able to easily twist and turn their bodies. Scientists from the Technion-Israel Institute of Technology and MIT are now attempting to copy that structure, to develop flexible-yet-effective armor for humans.

Led by Technion's Assistant Professor Stephan Rudykh, the team has already created a composite material that consists of stiff, overlapping outer "scales," combined with a layer of soft and flexible material underneath. The addition of the scales boosts the softer material's penetration resistance by a factor of 40, while reducing its flexibility by a factor of only five.

That reduced flexibility is still an issue, although the scientists state that by tweaking the characteristics of the material, its flexibility could be increased in areas such as the knees and elbows, while the penetration resistance could be maximized in vulnerable regions such as the upper body.

Rudykh additionally suggests that via 3D printing, the characteristics of the armor could be fine-tuned for use in different scenarios. These could include not only military and policing applications, but also the protection of space-walking astronauts against micro-meteors.

This isn't the first time we've heard about scale-inspired armor. A team at Northeastern University in Boston has also developed a scales-on-a-soft-substrate material, while researchers at the University of California, San Diego are looking into replicating the hard-but-flexible scales of the Arapaima fish.

While the Technion/MIT material has already been subjected to initial penetration tests, plans call for it to next be tested against fast-moving projectiles such as bullets. A paper on the research was recently published in the journal Soft Matter.